SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '651371470bc874cfdd67a38cc7eb835cb81831e23508b11c6291595e1fe74055' 
  AND token = '6wJqiGzJ/BsauzhhGl7Xu9oPz5qba87v6uJa9xJNUZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}